Wireless communication systems have become ubiquitous in society. Business and consumers use a wide variety of fixed and mobile wireless terminals, including cell phones, pagers, Personal Communication Services (PCS) systems, and fixed wireless access devices (i.e., vending machine with cellular capability). Wireless service providers continually create new markets for wireless devices and to expand existing markets by making wireless devices and services cheaper and more reliable. The price of wireless devices has decreased to the point where these devices are affordable to nearly everyone and the price of a wireless device is only a small part of the total cost to the user (i.e., subscriber). To continue to attract new customers, wireless service providers are implementing new services, especially digital data services that enable a user to browse the Internet and to send and receive e-mail.
However, addition of digital data services to a wireless network greatly increases the message traffic flowing between base stations and wireless terminals (i.e., cell phone, wireless laptop, fixed terminal, and the like). This is particularly true for the overhead channels (e.g., paging, common control channels). For example, if a subscriber operating a wireless laptop opens an e-mail application, a browser application, and a VPN connection to a remote server, a different set of control messages are transmitted between the base station and the wireless terminal (i.e., laptop) for each data session. This problem is exacerbated if the subscriber moves from the coverage area of an original base station into the coverage area of a new target base station. If one or more of the data sessions have been dormant (i.e., no traffic channel in use) for a period of time when the hand-off occurs, the dormant data sessions may be dropped during the hand-off unless a separate set of control messages are used to cause the hand-off of each data session from the original base station to the target base station.
For example, under current code division multiple access (CDMA) signaling procedures, each service instance (i.e., data session) must be re-activated separately as part of a hand-off. A CDMA mobile station (or other wireless-terminal) achieves this by sending an Origination message from the mobile station to the network base station. Thus, the mobile station must transmit either multiple Origination messages or multiple Enhanced Origination messages. Sending multiple instances of an Origination message or an Enhanced Origination message (EOM) causes unnecessary loading of the air interface and may cause delay in the handoff of multiple service instances. This is not an efficient way to re-activate multiple service instances.
Therefore, there is a need for wireless communication devices that are capable of re-activating multiple data sessions in an efficient manner. In particular, there is a need for an improved base station and an improved mobile station that can efficiently re-activate multiple dormant data sessions with a minimum amount of control channel messages.